1. Field of the Invention
The present invention relates to an ink housing device for supplying ink to a recording head and also to an inkjet recording device including the ink housing device.
2. Related Art
Japanese Patent No. 2725281 discloses a conventional ink housing device used in an inkjet recording device that ejects ink droplets onto a recording medium in accordance with input signals. The ink housing device includes an air-tight box-shaped ink cartridge whose internal space is divided into two chambers. An ink accommodating pouch made of compound resin is housed in one chamber, and a waste ink absorbing member is housed in another chamber. A sidewall of the one chamber is formed with a through hole into which a rubber stopper is inserted. The rubber stopper seals off one end of an ink outlet tube extending from the ink accommodating pouch. An ink supply needle that is connected through a supply tube to a recording head is penetrating the rubber stopper into the ink outlet tube. With this configuration, ink inside the ink accommodating pouch is supplied to the recording head through the ink outlet tube, the needle, and the supply tube.
One side wall of the another chamber is formed with a through hole, into which a waste-ink inlet made of resilient rubber is inserted. A discharging needle attached to a tip end of a waste ink tube that is connected to a purging member is penetrating through the waste-ink inlet to locate near the waste ink absorbing member. With this condition, defective ink and air bubbles drawn out of the recording head during purging operations are collected into the another chamber through the waste ink tube and the discharging needle. Thus collected ink is absorbed into the waste ink absorbing member, and collected air is discharged out of the chamber through a discharge port formed in an upper wall of the another chamber.
Japanese Patent Application-Publication No. HEI-4-211963 discloses a different type of ink housing device that includes a box-shaped air-tight cartridge casing. A waste-ink absorbing member, a non-absorbing sheet (a sheet that does not absorb liquid) positioned along a wide upper surface of the waste-ink absorbing member, and an ink accommodating pouch that accommodates ink are all housed inside the casing. A sealing cap made of resilient rubber is engaged inside a through hole formed in a side wall of the casing, and is connected to a tube housed inside the ink accommodating pouch. An ink discharging tube is inserted through a sidewall into the casing so that its leading end locates above the non-absorbing sheet. When waste ink is introduced through the ink discharging tube and dropped onto the non-absorbing member, then the ink quickly spreads along its surface and then absorbed into the ink absorbing member. Air bubble collected into the casing would be discharged through a port.
However, according to the above-described conventional ink housing devices, the ink absorbing member and the non-absorbing sheet increase production costs of the device. Also, when the ink absorbing member with waste ink absorbed therein is left for a long period of time, then volatile materials of ink evaporate, so that the ink solidifies inside the ink absorbing member. The solidified ink prevents capillary effect of the ink absorbing member on its surface. Further, if air bubbles reside inside the casing, internal pressure of the casing increases, so that waste ink leaks out of the casing through the through holes, thereby dirtying internal of an inkjet recording device.
Moreover, when the through holes are faced downward by tilting or turning an ink cartridge upside down while handling the ink cartridge, then waste ink more easily leaks out of the casing.
In view of foregoing, it is an object of the present invention to overcome the above problems and also to provide an inexpensive ink housing device preventing ink leakage without using an ink absorbing member and also to provide an inkjet recording device including the ink housing device.
In order to overcome the above and other objects, according to the present invention, there is provided an ink housing device including a casing and an air permeable film. The casing is formed with an ink accommodating chamber for accommodating an ink accommodating pouch and a waste ink chamber into which a waste ink is collected. The casing is formed with a through hole connected to the waste ink chamber. The air permeable film seals the through hole.
There is also provided an inkjet recording device an inkjet head, an ink cartridge, a supply tube, and a discharging tube. The ink cartridge includes an ink accommodating pouch accommodating ink, a casing formed with a waste ink chamber and an ink accommodating chamber that houses the ink accommodating pouch, and an air permeable film. The casing is formed with a through hole connected to the waste ink chamber. The air permeable film seals the through hole. The supply tube introduces the ink from the ink accommodating pouch to the inkjet head. The discharging tube introduces waste ink from the inkjet head into the waste ink chamber.